From b0ae21860621da0f2efd6c08dc1f8af7ab2fee55 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andrzej=20G=C5=82uszak?= <andrzej.gluszak@jetbrains.com>
Date: Wed, 11 Oct 2023 15:12:06 +0200
Subject: [PATCH] Fix #116631

---
 compiler/rustc_ast/src/ast.rs             | 20 ++++++++++++++++++++
 compiler/rustc_ast_lowering/src/format.rs |  8 ++++++--
 tests/ui/fmt/issue-116631.rs              |  3 +++
 tests/ui/fmt/issue-116631.stderr          | 11 +++++++++++
 4 files changed, 40 insertions(+), 2 deletions(-)
 create mode 100644 tests/ui/fmt/issue-116631.rs
 create mode 100644 tests/ui/fmt/issue-116631.stderr

diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index e8cbd7b69fbe0..af1c4766177e8 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -1795,6 +1795,26 @@ pub enum LitIntType {
     Unsuffixed,
 }
 
+impl LitIntType {
+    pub const fn max_literal_value(&self) -> u128 {
+        match self {
+            LitIntType::Signed(IntTy::I8) => i8::MAX as u128,
+            LitIntType::Signed(IntTy::I16) => i16::MAX as u128,
+            LitIntType::Signed(IntTy::I32) => i32::MAX as u128,
+            LitIntType::Signed(IntTy::I64) => i64::MAX as u128,
+            LitIntType::Signed(IntTy::I128) => i128::MAX as u128,
+            LitIntType::Signed(IntTy::Isize) => isize::MAX as u128,
+            LitIntType::Unsigned(UintTy::U8) => u8::MAX as u128,
+            LitIntType::Unsigned(UintTy::U16) => u16::MAX as u128,
+            LitIntType::Unsigned(UintTy::U32) => u32::MAX as u128,
+            LitIntType::Unsigned(UintTy::U64) => u64::MAX as u128,
+            LitIntType::Unsigned(UintTy::U128) => u128::MAX,
+            LitIntType::Unsigned(UintTy::Usize) => usize::MAX as u128,
+            LitIntType::Unsuffixed => u128::MAX,
+        }
+    }
+}
+
 /// Type of the float literal based on provided suffix.
 #[derive(Clone, Copy, Encodable, Decodable, Debug, Hash, Eq, PartialEq)]
 #[derive(HashStable_Generic)]
diff --git a/compiler/rustc_ast_lowering/src/format.rs b/compiler/rustc_ast_lowering/src/format.rs
index 45a9bebfcf627..410858a2f19c4 100644
--- a/compiler/rustc_ast_lowering/src/format.rs
+++ b/compiler/rustc_ast_lowering/src/format.rs
@@ -128,9 +128,13 @@ fn inline_literals(mut fmt: Cow<'_, FormatArgs>) -> Cow<'_, FormatArgs> {
             {
                 literal = Some(s);
             } else if let token::LitKind::Integer = lit.kind
-                && let Ok(LitKind::Int(n, _)) = LitKind::from_token_lit(lit)
+                && let Ok(LitKind::Int(n, ty)) = LitKind::from_token_lit(lit)
             {
-                literal = Some(Symbol::intern(&n.to_string()));
+                // Check if n fits in the type of the argument. If it doesn't,
+                // simply don't inline the literal here, the error will be emitted at a later stage.
+                if n <= ty.max_literal_value() {
+                    literal = Some(Symbol::intern(&n.to_string()));
+                }
             }
         }
 
diff --git a/tests/ui/fmt/issue-116631.rs b/tests/ui/fmt/issue-116631.rs
new file mode 100644
index 0000000000000..fb8fc50ab8d56
--- /dev/null
+++ b/tests/ui/fmt/issue-116631.rs
@@ -0,0 +1,3 @@
+fn main() {
+    format_args!("{}\n", 0xffff_ffff_u8); //~ ERROR literal out of range for `u8`
+}
diff --git a/tests/ui/fmt/issue-116631.stderr b/tests/ui/fmt/issue-116631.stderr
new file mode 100644
index 0000000000000..dafbca6acd187
--- /dev/null
+++ b/tests/ui/fmt/issue-116631.stderr
@@ -0,0 +1,11 @@
+error: literal out of range for `u8`
+  --> $DIR/issue-116631.rs:2:26
+   |
+LL |     format_args!("{}\n", 0xffff_ffff_u8);
+   |                          ^^^^^^^^^^^^^^ help: consider using the type `u32` instead: `0xffff_ffff_u32`
+   |
+   = note: the literal `0xffff_ffff_u8` (decimal `4294967295`) does not fit into the type `u8` and will become `255u8`
+   = note: `#[deny(overflowing_literals)]` on by default
+
+error: aborting due to previous error
+